You can look at tons of formally successful businesses that took in too many MBA types and lost their edge (e.g. IBM, Microsoft, HP, Cisco, et al). Google is also starting to go in that direction. Amazon has actually been fairly successful in avoiding that culture (partly due to their own internal culture being almost anti-MBA philosophy).
I'd happily hire an accountant, a lawyer, or even an economist. They're all specialists who bring different knowledge and perspectives to the table. I'd avoid hiring an MBA as they're largely useless people who just want to gum up the works with bullshit.
Engineers for engineering managers aren't perfect, but at least they aren't so far removed as MBAs are. At least once in their lives they knew what it took to deliver, and I'd prefer to train up an engineer into a decent manager than take in a pre-trained MBA.